Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-resistant Staphylococcus epidermidis (MRSE), drug-resistant Streptococcus pneumoniae, multi-drug resistant Mycobacterium tuberculosis and vancomycin-resistant enterococcus (VRE) present worldwide are the most difficult issues in current clinical anti-infection treatment [Exp. Opin. Ther. Patents, 2000, 10 (9): 1405; Exp. Opin. Ther. Patents, 2004, 14 (9): 1309]. Facing the challenges by multi-drug resistant bacteria, antimicrobial agents with completely new action mechanisms must be developed. Oxazolidinones are a new class of antimicrobial agents, and they have potent antibacterial activity against multi-drug resistant Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococcus, and penicillin-resistant Streptococcus pneumoniae etc., as well as sensitive Gram-positive bacteria (Angew Chem. Int. Ed., 2003, 42: 2010; Current Topics in Medicinal Chemistry, 2003, 3: 1021). Oxazolidinones inhibit bacterial protein synthesis in its early stage, and their new structure and unique antibacterial mechanism different from currently available antibiotics has drawn the attention of many pharmaceutical companies and research institutions. Additionally, literatures have already reported many oxazolidinone compounds of different structure types (Expert Opin. Ther. Patents, 2008, 18, 97-121; Anti-Infective in Medicinal Chemistry, 2008, 7, 32-49; Anti-Infective in Medicinal Chemistry, 2008, 7, 258-280). Developed by the Upjohn Company (USA), linezolid was approved by the FDA in 2000 and firstly launched in the United States under the trade name Zyvox, and thus became the first approved oxazolidinone drug to be used clinically. However, existing drugs have weak antibacterial activity and side effects such as bone marrow suppression, therefore a need to research and develop new drugs with stronger antibacterial activity is warranted.